I found her! On the second frame of brood I looked at. I caught her on video for you - look for her white blob, a mark I put on her at the end of last year so I could find her easily. She's sort of sways as she move like a big-hipped lady weaving between people in a crowed bar or station. I packed up after seeing her as I could see she was laying well, she looked good, the hive was busy and I gave them some fondant for additional food in case the weather stops them getting out for a few days. it's a high risk starvation time of year this as the colony is kicking into action, and has little stores left from last summer so needs fresh pollen and nectar - cold weather and rain can easily stop them getting it.